April 21, 2009
North of the border a controversy is starting to gain steam in the nation’s largest city, Toronto. The city has proposed a by-law that would make ‘green roofs’ mandatory in new construction of condos higher than 7 storeys and office or retail complexes greater than 54,000 square feet (about 1/4 of a Wal-Mart Supercenter). The proposed law would require 30-60% of the surface area of buildings’ roofs to be green (depending on the size of the building) and violators would be subject to fines up to $100,000.
A green roof is partially or completely covered with vegetation and soil that has been planted over a waterproof layer on top of the standard roof of a building. The benefits of these roofs are many, including reduced storm water runoff, reduced noise pollution, and increased longevity of the roof by protecting it from natural elements.
Green roofs are also getting attention in this era of greenhouse gas mitigation because of their potential to reduce energy use. The layer of soil and vegetation above the traditional roof provides an additional layer of insulation that reduces cooling in the summer and heating in the winter. Green roofs also reduce the severity of the urban heat island, which is the increase of city temperatures by several degrees over surrounding rural areas. A reduction of the heat island effect means a cooler city and less energy used for air conditioning.
So why all the fuss in Toronto? A battle is evolving between the City of Toronto and the powerful land development industry. For several years the city has been led by a pro-environment mayor who is determined to make Toronto a global centerpiece of environmental responsibility. Some representatives of the city council are so dedicated to the green roof plan that they want it broadened in scope. Deputy Mayor Joe Pantalone has asked city staff to deliver an expanded green roof by-law that would include schools, low-rise commercial buildings, and even private residences.
The developers are publicizing the additional costs involved with building a green roof, which they claim is $18-$28 per square foot over traditional roofs. They argue that this will result in more expensive housing, office space, and retail goods, costs that will be passed on to the tax-paying consumers of these products.
The city has decided to postpone a scheduled April council vote so that the issue can be discussed by the Toronto Planning and Growth Committee again on May 6.
A number of questions came to mind as I reviewed this intriguing story:
- Instead of strong-arm regulatory tactics, wouldn’t incentives or tax breaks be a much more appealing way to encourage green roof construction? This voluntary approach has been promoted by the developers as a reasonable alternative to the proposed by-law
- Has the City of Toronto researched the realities and benefits of implementing and maintaining these roofs on such a large scale? Lawrence Solomon of the Financial Post raises some excellent points and encourages the city to be deliberate and proceed with caution. A pilot project and comprehensive life cycle assessment of green roofs would be logical approaches before approving a city-wide by-law
- Most importantly, is the city overstepping its bounds by trying to force this kind of expensive building construction? There are a myriad number of ways that the government influences the construction of buildings. Often this is in the name of public safety, such as sprinkler regulations and electrical codes. Can a by-law that has been proposed to combat climate change be considered a public safety law? Or is this an example of a city going too far by trying to regulate a component of construction that is best left to market-based approaches?
If this by-law does pass, it will be interesting to see if this kind of regulated green development policy will spread to other cities in North America.
Stephen Boles is co-founder of Kuzuka, a marketplace website that will bring a new level of convenience and confidence to carbon offset customers and provide consulting services to organizations that want to assess and reduce their carbon footprint.